The art of detection of fluid flow is replete with several classifications of inventions indexed for different purposes, say based on type of use involved versus their principles of operation. I am unaware of any detector or method which has cascaded the output effect to detect an ultrasmall change in transient flow conditions under a variety of occurrences, especially say from a heat sensing position completely exterior of the fluid-carrying body while maintaining the integrity of the interior of the body intact, i.e., without providing openings through the body itself.
In my previously filed applications of record, the transducer-meters of those disclosures are positioned completely exterior of the relief line (or series of relief lines) to be monitored (i.e., the relief line is not penetrated by openings). Monitoring variations in fluid flow is based on the assumption that the total system operations can be described with reference to two sequentially occurring temperature conditions: (i) a steady state temperature condition in which the relief line carrying the fluid and the air surrounding the meter are at the same temperature; and (ii) a transient condition in which change in fluid flow, say from a no-flow to a flow condition as a control valve opens, provides a mass of fluid adjacent the meter at a temperature that differs sufficiently from that of the surrounding air to cause the generation of a transient heat flux detectable by the meter.